1. Field of the Inventions
The present inventions relate generally to energy conversion.
2. Description of the Related Art
Energy conversion devices, such as vane motors, piston motors and turbines, may be used to convert a compressed gas stream into mechanical work. Vane motors and most piston motors do not allow the gas to significantly expand, and the work produced is the product of the volume of gas consumed at the intake times the pressure difference between intake and exhaust. Turbines are expansion-based devices and produce more work from a given gas stream than non-expansion devices. Turbines must run at relatively high blade speeds and, accordingly, are well suited for relatively large applications. As the size of the turbine blades decreases, the speed at which the turbines must rotate increases. The increase in rotational speed makes smaller bladed turbines harder to build and decreases their lifespan, as compared to their larger counterparts. The present inventor has, therefore, determined that other types of expansion-based energy conversion devices would be desirable.